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  • Flexible Duct Connector
  • Flexible Duct Connector
  • Flexible Duct Connector

Flexible Duct Connector

  • Super engineering and developing ability to solve your problem
  • Different levels of products to fit different environments
  • Full experience to guide you to install the products

Biyang Flexible Duct Connector is a kind of duct fittings to solve the noise and vibration problems caused by the blower, fans, and other equipment in the ventilation systems.  Biyang Flexible Duct Connector includes Canvas Duct Connector, Polyester Duct Connector (also named PVC Duct Connector), and Glass Fiber Duct Connector.

These airtight duct connectors are can be used in different environments, such as hot air ducting and high temperature area to solve your noise headache.  As the leading Flexible Duct Connector supplier, Biyang has several kinds of products.  Canvas Duct Connector, or Canvas Flexible Duct Connector, as the most common and pricing competitive Flexible Duct Connector product, is made of galvanized steel and canvas fabric.  This can be used in the normal temperature area.

The galvanized steel sheet is rust resistant and can be easily attached to the metal ducting.  The canvas fabric is soft but durable which makes the connector flexible but also strong.  The combination of these two materials makes a good choice for your air duct flexible connector and HVAC flexible duct connector.  With very competitive pricing, Biyang Canvas Duct Connector can simply solve your problem for most common environment applications.

Polyester Duct Connector is Biyang’s most popular Flexible Duct Connector.  Firstly, Polyester Duct Connector is fire resistant and can be worked as a fire rated flexible duct connector.  Biyang Flexible Duct Connector of polyester can work in the -30℃-120℃.

Secondly, Polyester Duct Connector is more resistant than Canvas Duct Connector, with 3000x2090N tensile strength and 288.5×246.6N anti-rip intensity.  Thirdly, it is a balance between cost and product features.  This is why most customers will love our Biyang Polyester Duct Connector.

Glass fiber Duct Connector is Biyang’s high end product, which is also called High Temperature Flexible Duct Connector.  This Biyang Flexible Duct Connector has the most competitive features in heat resistance and strength.

It can bear  -30℃-280℃, 2300x1860N tensile strength, and 253.6×180.5N anti-rip intensity.  In a tough and rough environment, Biyang Glass Fiber Duct Connector can always be the best choice.

Biyang Flexible Duct Connectors have all common sizes for HVAC ductwork and are available in 25m, 30m, 45m, and 50m length.  Of course, custom length can be also made based on your particular request.

Biyang Flexible Duct Connectors are easily cut into small pieces without requiring complicated tools when it comes to installation.  When cutting, Biyang suggests that you measure the overall connection size of the blower or fan and plus additional 2.5-4cm length.

In addition, Biyang provides two methods for flexible duct connection details.  One is to glue the overlap section.  Of course, the glue should be strong.  The other is to use a special staple to nail the overlap parts.

For details of cutting direction and flexible duct connector installation, please download Biyang catalogue.  After cutting, Biyang Flexible Duct Connector can both work for round and rectangular ductings.

As one of the most professional Flexible Duct Connector suppliers in China, Biyang has kept on developing new series of products to fit different applications, such as round flexible duct connector, rectangular duct connectors, flexible plenum connector, neoprene flexible duct connector to meet your different requirements.

If you have any questions, just send us a mail or message to solve your flexible ductwork connector problems.

ProductFlexible Duct Connector
MaterialGalvanized Steel & canvas/polyester/glass fiber
Size35+60+35mm, 45+60+45mm, 45+70+45mm, 45+75+45mm,


Length25m, 30m, 50m

Flexible Duct Connector: The Ultimate FAQ Guide

1) What is a Flexible Duct Connector?

Flexible duct connector

Flexible duct connector

Flexible Duct Connector is a ductwork fitting useful in the elimination of vibrations and noises for residential and industrial applications while carrying out thermal insulation.

All air duct installations for HVAC systems are connected to mechanical appliances having a blower or fan.

Rattles, noises, or vibrations from the blower or fan operation get transferred into the metal ducts which pass on the noises all through the system.

For you to cut off the vibrations and noises to the source, you must insert flexible duct connector between the equipment and the ductwork.

The duct connector is a flexible air-tight joint comprising of fabric which is attached to sheet metal on both ends.

Parts of flexible duct connector

Parts of flexible duct connector

The fabric used to make flexible duct connector can be, for example, a glass fiber having polyurethane coating or polyester having PVC coating, which is attached to sheet metal on both ends.

The material used to make the sheet metal can either be stainless steel or galvanized steel.

2) Are Flexible Duct Connectors UL Classified?

Absolutely, Underwriters Laboratories, Inc. rigorously test and classify flexible duct connectors in line with UL 181.

The flex duct connectors have to pass the 12 tests set in the standard, and you can identify UL tested and classified flexible duct connector by the UL label displayed on them.

3) Where are Flexible Duct Connectors Used?

Flexible duct connector

Flexible duct connector

Flexible duct connectors are produced in differing sizes and thickness for use in industrial, light commercial, commercial and residential applications.

All mechanical equipment such as ventilation fans, fan coil units, and air handling units produce noise and vibration when in operation.

Usually, you will find flexible duct connectors located within close vicinity to any ventilation device that may generate vibration and/or noise.

When installing the flex duct connectors, you should pull them open, though a little shy of being tight.

A closed connector will block airflow and may be unsuccessful in its primary purpose of eliminating vibrations and noises.

4) Why use Flexible Duct Connector in HVAC Systems?

Flexible duct connectors are HVAC fittings used as joints between the appliance and the ducts to isolate the noises and vibrations in a HVAC ductwork system.

They enable the fast development of flexible joints to suppress the transmission of vibrations between the HVAC equipment and related ductwork.

Installation of the flexible duct connector is usually between the outlet of the equipment and the ducts inlet.

In contrast to hard duct, flexible duct connectors as well permit for a modest offset between the HVAC equipment and the ductwork.

5) What is the Best Seam for Flexible Duct Connector?

Double-fold offset seam gives superior tear resistance, fabric protection and holding power whilst adding structural stiffness, still cuts and functions easily.

This style of connection makes sure that you get an airtight seal that is difficult to damage when fabricating the duct connector into its final shape.

The double-fold offset seam equally adds structural stability to the flex duct connector, which implies that the possibilities of failure because of under- or over-pressure issues are very slim.

6) How do You Specify Flexible Duct Connector?

You have to issue the right specification of Flexible duct connector to ensure that you get the right product for your HVAC system.

Below is a typical example how you specify flex duct connector to your supplier.

7) Which Fabrics are Used in Flexible Duct Connector?

The most important component of the flexible duct connector is the fabric which you choose to fit the typical requirements of every HVAC system installation.

The following varieties of fabric are available for you to select from:

i. Vinyl

Vinyl is the right choice of fabric for flexible duct connector on HVAC applications where you need an economical flexible connection.

It is the commonly applied fabric for all ductwork installations particularly for residential applications because of it is high abrasion resistance and high tear strength.

Vinyl is the appropriate flexible duct connector fabric for airtight, waterproof and low to medium pressure ductwork system.

ii. Neoprene BS

Flex duct connector having Neoprene fabric is suitable for use in applications requiring high mechanical strength. Neoprene is exceptionally resistant to the majority of alkalis, toxic fumes, and gasoline.

iii. Silicon

Fabric made from silicon has a special silicon rubber layer that features exceptional resistance to low and high temperatures.

This type of fabric will not burn and releases negligible fumes when subjected to open flame.

Flexible duct connectors with silicon fabric are highly suitable for projects where high temperature is of primary interest in both outdoor and indoor HVAC system installations.

iv. Hypalon

Flexible duct connectors made of Hypalonfabric are the best option for rooftop or areas experiencing direct sunlight. You can use them for more outdoor applications.

Ultraviolet radiations do not affect Hypalon fabric.

Therefore, you can install flexible duct connectors made from it close to U.V. ray filtration systems and electrostatic air cleaners with utmost confidence.

Hypalon has a higher abrasion resistance than Neoprene, excellent aging qualities, a moderately broader operating temperature range and resists a variety of chemicals.

v. Polyurethane

Also referred to as PUL fabric, Polyurethane is a waterproof fabric, usually polyester, although maybe a poly blend or cotton material which goes through heat lamination to form a polyurethane layer.

This flexible duct connector fabric is lightweight and exceptionally durable.

Being flexible and easy to work makes polyurethane a good material for flex duct connectors.

In addition, to have high resistance to abrasion, it is possible to make PUL fabric airtight to resist humidity and water and fire-retardant.

Despite being delicate in construction, flexible duct connectors with Polyurethane fabric have a longer resistance period to elevated temperatures.

vi. Canvas

The traditional option utilized for general air conditioning and ventilating projects and applications in waterproof and airtight constructions, both outdoors and indoors.

8) Can Flexible Duct Connectors Prevent Noise and Vibration Transmission?

Flexible duct connector

Flexible duct connector

Yes, the primary purpose of flexible duct connectors is to prevent the transmission of vibrations and noises between the ductwork and the HVAC equipment.

In an HVAC system, rotating appliances and the movement of fluid and air across the pipes and ducts usually generate most sounds or noises.

This movement leads to vibrations, noises or sounds which you can effectively isolate using flexible duct connectors.

You can as well eliminate vibrations, sounds, and noise by ensuring proper designing of the HVAC system, and this includes:

  • Selecting a suitable duct silencer – It should be a silencer that does not increase total static pressure of the fan. A static pressure loss equal to or less than 0.35 inches of water significantly lowers noise level.
  • Design the air distribution system to reduce turbulence and flow resistance. When there is high flow of air resistance, you will need high fan pressure.

This will consequently lead to elevated noise level from the fan, especially when frequencies are low.

  • Air flowing through areas sensitive to sound should be low. You can achieve this by increasing the size of duct system which will reduce level of noise and turbulence due to airflow.
  • Reduce the utilization of volume dampers close to registers, grilles, and diffusers in acoustically crucial situations.
  • Duct transitions should be less than 15 degrees of included expansion angel failure to which the system will be noisy.
  • Reduce flow-generated noise by duct branch takeoffs or elbows whenever possible by positioning them at least 4-5 duct diameters away from each other.

9) What are the Different Configurations of Flexible Duct Connector?

Flexible duct connectors are available in different types of configurations.

Let’s look at the two common configurations of flex duct connectors.

· Rectangular Flexible Duct Connectors

Rectangular flex duct connectors are instrumental for creating fabric compensators.

They assist in avoiding the transfer of vibrations in rectangular ductwork and appropriate for acoustic decoupling.

Thus, rectangular flex duct connector often functions as a connecting component between fans or devices and HVAC rectangular ducts.

· Circular Flexible Duct Connectors

This type of flexible duct connectors particularly finds application in connecting two plain or spiral round ducts.

The primary role of circular duct connectors is to prevent the transfer of vibrations and noise to the circular duct system.

This in return enhances the acoustic performance of the ductwork installation.

They come in different dimensions and flame retardant materials which boosts their temperature resistance.

10) What is the Best Flexible Duct Connector Material?

Neoprene is popular in HVAC systems.

It is a perfect alternative over other available flexible duct connector material.

Neoprene is widely used and most frequently specified flexible duct connector fabric since it retains its aging characteristics and flexibility over a long period of time.

The fabric provides a waterproof and airtight performance, has an exceptional aging feature and flex life, and excellent burst strength.

It has a base fabric of knitted fiberglass that has a double coat made up of polychloroprene.

Neoprene flexible duct connectors have coils of fabric on both ends to galvanized steel.

Alternatively, they may come only as a fabric for some uses.

The fabric is highly suitable for applications requiring heavy mechanical strength.

You can use neoprene in high-pressure and high-velocity ductwork system.

Besides, it is suitable where the flexible duct connector is exposed to adverse atmospheric conditions or toxic fumes.

It is a tough, reliable product which you can use with great trust in general HVAC applications.

11) Are Flexible Duct Connector NFPA 701 Certified?

Yes, the fabric used to make the most flexible duct connectors meet NFPA 701 standards (both 90A and 90B).

12) What is a Fire Rated Flexible Duct Connector?

Fire rated flexible duct connector is one manufactured using approved flame-retardant fabric.

The fabric can withstand elevated temperatures when dealing with air and fumes.

Polyurethane and neoprene are the materials commonly used to manufacture most fires rated flexible duct connector.

These fabric types are flame retardant and chemically materials.

They offer exceptional durability when under extreme abrasion.

13) Does Biyang Manufacture Insulated Flexible Duct Connector?

Yes, Biyang has a full range of Insulated flexible Duct Connectors which apply fiberglass insulation enclosed between two layers of fabric.

Biyang flexible duct connector

Biyang flexible duct connector

The numerous options of fabric available in insulated models, makes sure that you can use the flexible duct connector for all possible kinds of ductwork installations.

For acoustically treated supply ducts and ductwork, it is essential that you also insulate the fabric of the flex duct connector in addition to the insulation installed on the ducting.

This ensure that the flexible duct connector attains maximal effectiveness.

14) How Much Does Biyang Sell Flexible Duct Connector?

Biyang has set a very pocket friendly price for their flexible duct connectors.

The price depends on the style, size and quantity of duct connector you would want to buy.

Typically, the price range is between USD 1-5 per piece of flexible duct connector.

15) How does Biyang Package Flexible Duct Connector for Shipping?

In a Standard package, Biyang package their flexible duct connector in a paper carton with each piece inside a plastic film.

Pallets are as well available for ease in unloading the shipment.

16) Can Biyang Flexible Duct Connector be Cut to Size?

Yes, you can easily cut to size Biyang Flexible Duct Connectors without requiring complex tools during installation.

When cutting to size, Biyang recommends that you determine the overall connection size of the fan or blower and add extra 2.5-4cm length.

17) What Other Duct Fittings Does Biyang Export?

Biyang HVAC Duct Fittings encompass all types of connection and transition fitments for HVAC ductwork.

Biyang has a variety of products and specifications to meet almost all of its customers’ requirements.

We are a one-stop shop that will satisfy all your HVAC ductwork needs.

Apart from flexible duct connectors, we also offer the following duct fittings:

  • Hose Clamps
  • Duct transitions
  • Duct Elbow
  • Duct Reducer
  • Duct boot
  • Duct splitter
  • HVAC Saddle Tap
  • Line set cover

Contact us todayfor your all your HVAC systems accessories.

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